Ok, I messed up as I was trying to change Guruplug Server plus to boot from SD card but it didn't work. And I did not jot down the settings that I have for my guruplug, now it does not boot at all and stuck at "NET: Registered protocol family 10". I would like to revert back to factory defaults, booting from the usual NAND. How do I do that? Could any kind soul in this forum send me the correct uboot commands to type?

You did a good job to preserve the system condition this make debug much easier

First you need to clarify your intention, you said you want to "boot from SD", do you mean you want the rootfs load from SD or you want u-boot load kernel from SD? To me "boot from SD" mean make uboot load kernel from SD which is not happening for you base on the info you provided. however you are already load and boot from NAND as is now.

currently your setting use NAND partition 2 for rootfs and the file system is "ubifs" and you were successfully boot up but you may have mis-configured your rootfs where in its /etc/fstab it may be looking stuff from SD, your problem is because the SD is on USB which is slow to come up so it throw off the boot sequence since it can not get all the essential directories need for linux system.

If my analysis is correct then you can try to boot into single user mode by modify your "bootargs_root" append word "single". this should let you boot to shell prompt at which point you can correct your /etc/fstab and start again.

BTW, the "NET: Registered protocol family 10" is refer to IPV6, so it most likely it load the module but missing something in /etc so it stuck in there.

>First you need to clarify your intention, you said you want to "boot from SD", do you mean you want the rootfs load from SD or you want u-boot load kernel from SD?My rootfs was full. So I was thinking to boot my rootfs from SD, I am not interested in booting the kernel from SD (what is the benefits by the way? ).

Yes, I have not change the /etc/fstab, as I am not able to get into the OS. I think if I boot using single mode, I will get the root prompt and will be able to change the fstab?

Once you got into single user mode you are root and can change anything you want.

I am not 100% sure I understand your situation, you said "Yes, I have not change the /etc/fstab", so if you have not change /etc/fstab than my analysis is wrong and you do not need to go into single user mode to change anything.

Anyway, if you want to use SD as your rootfs then change your "bootargs_root" to have "root=/dev/sdc[partition number where your rootfs is] rootwait". This should let you boot from SD.

Having kernel on SD allow you to upgrade kernel easier, I think you are using debian alike distro. I think it have some simple upgrade script to upgrade kernel.

2) copy files of Guruplug into microSD as:#cp -axv / /mnt/sdcard #cp -av /dev /mnt/sdcard By about two steps, the bootable microSD is available

3) The next is how to boot the microSD, do#ls -l /dev/sd*brw-rw---- 1 root floppy 8, 0 2009-08-08 16:48 /dev/sdabrw-rw---- 1 root floppy 8, 16 2009-08-08 16:48 /dev/sdbbrw-rw---- 1 root floppy 8, 17 2009-08-08 16:48 /dev/sdb1the major and minor device numbers for ‘/dev/sdb1′ which I put the rootfs on, are 8 and 17 respectively.That number needs to be converted to hex, for entry in Uboot -- 8,17 in decimal converts to 8,11 in Hex, for entry in Uboot this will be entered as ’0811′.

4) Reboot the GuruPlug and this time hit any key before the system boots into Debian. Once at the Marvell prompt type:Marvell>> nand read.e 0x6400000 0x100000 0x400000Marvell>> setenv bootargs console=ttyS0,115200 root=0811 rootdelay=10Marvell>> bootm 0x6400000